Governing mechanism for fuel injection pumps



May 16, 1950 F. BUCK ETAL GovERNING MECHANISM FOR FUEL INJECTION PUMPS Y 4 Sheets-Sheet 1 Original Filed Sept. '7, 1940 4 Sheets-Sheet 2 F. BUCK ET AL May 16, 195o GOVERNING MECHANISM FOR FUEL INJECTION PUMPS Original Filed Sept. '7, 1940 May 16, 1950 F. BUCK ETAL 507,689

GOVERNING MECHANISM FOR FUEL INJECTION PUMPS Original Filed Sept. 7, 1940 4 Sheets-Sheet 5 Fig 7 la 3e O ,12' r1. 1,7 39 [n1/@nim i3: Fosi'er BULB,

.fm Fred 1J BarI/ndzf O lo 13 H man, Bowers May 16, 1950 F. BUCK ErAl. 2,507,639

GOVERNING MECHANISM FOR FUEL INJECTION PUMPS Original Filed Sept. 7, 1940 4 Sheets-Sheet 4 Z1/6' Il@ Patented May 16, 1950 GOVERNING MECHANISM FOR FUEL INJECTION PUMPS Foster Buck, Lisle, Fred W. Barbknecht, Palos Heights, and Raymon Bowers, Western Springs; lll., assignors to International Harvester Company, a corporation of New Jersey Continuation of application Serial No. $551,796, This application April 8, 1946, Serial No. 660,566

September 7, 1940.

12 Claims.

This invention relates to a governor mecha.- nism for fuel injection pumps. More specifically, it relates to governing mechanism particularly adapted to regulate an injection pump in which the fuel iniected per stroke decreases with a decrease in speed, and this application is a continuationof our copending application Serial No. 355,796, led September 7, 1940, since abandoned, for Governing mechanism for fuel injection Dumps.

For fuel injection engines both of the compression ignition type and the typeA using spark ignition, the piston controlled port 'design of pump has come into extensive use. Said pump operates by utilizing ports in the barrel or bushing for the inlet of fuel and for the by-pass of fuel, the injection pump plunger being formed with control edges and passages providing for regulating the amount of fuel discharged by depending upon the angular position of the piston. To provide governing means, some type of mechanism is provided for connecting a governor mechanism to the piston for changing its angular position in accordance with the speed of the engine.

Diillculty has been encountered in providing n the proper injection for different engine speeds due to the change in the amount of fuel injected by a pump of the piston controlled port type with variations in speed. This change is due to the increased amount of leakage at slower speeds and to other factors 'inherent in a pump of this design.

In the usual centrifugal type of governor, a single or compound spring is utilized, acting in opposition to the force obtained by centrifugal weights driven at a high speed from gearing connected to the engine crankshaft. As it is necessary to have a definite stop for full load operation of the engine for any given speed, a condition arises during an overload condition in which not only is there a decrease in speed with a constant decrease in power output, but also with the decrease in speed there is a decrease in the amount f fuel injected per stroke. 'I'his results in an accelerated reduction in speed amounting to a rapid stalling of the engine. The result desired is that the governor continues not only'to inject the same amount of fuel per stroke, but that during the temporary condition an excess of fuel be injected. The full load position on most engines is established somewhat below the maximum power output of the engine and somewhat below the smoke range in compression ignition engines. There is no objection to injecting additional amounts of fuel for a short period during a so-called over- 2 load condition when there is a substantial decrease in speed.

The object of the present invention is to modify the conventional governor control in such a way that the normal balance spring on the governor is held out of action during a condition resulting from decreased'speed at a full load condition of operation. During such period an auxiliary variable rate spring is utilized to maintain or increase the amount of fuel injected during a decrease in speed. Such constructions using a constant rate spring are not basically new in the governor art, being shown in the Drunder Patent 1,260,311 and Leissner Patent 1,260,922. Each of these patents shows a governor in which a weak constant rate spring is used at a lower speed operation with a stronger constant rate spring coming into opera.- tion at a higher speed operation. The reverse operation, from high speed to a lower speed, acts to first utilize the stronger spring and to subsequently utilize the weaker spring. It is in a governor mechanism of this type as applied to a new and different problem of torque control that applicant has made an improvement.

In the drawings:

Figure 1 shows the side of a, pump structure with portions of the casing broken away to show portions of the governor mechanism and the governor regulating device incorporated` in the mechanism between the centrifugal weights and the pump control rack;

Figure 2 is a vertical section through the pump casing of Figure 1 taken substantially on the line 2 2;

Figure 3 is a view of one of the control members of the governor mechanism including the variable rate spring carried thereby;

Figure 4 is a bottom plan view of the structure shown in Figure 3;

Figures 5 and 6 are details showing one of the adjustable abutments for the variable rate spring;

Figures 7, 8, and 9 are diagrammatical illustrations of the governor mechanism showing three different positions of operation;

Figure 10 is a sectional view taken vertically and centrally through a fuel injection pump; and

Figure llis a fragmentary sectional view taken at right angles to the view in Figure 10 and illustrating the structural .relation of the upper end of the pump plunger and fuel ports cooperative therewith in the feeding and regulating of the amount of fuel delivery.

Q As the governor mechanism of this invention may be utilized with any fuel 'injection pump, such as the piston control port type shown in the Baur Patent No, 1,944,858, only such parts of a pump casing have been shown as are necessary to illustrate the invention. In Figure l, the lower left-hand portion of a pump casing I has been broken away to show a conventional centrifugal weight assembly. Governor weights II, as also shown in Figures 7, 8, and 9, and constituting a form of force exerting means are pivoted on a carrier I2 and are provided with thrust portions |2' positioned to engage a flange i4 on a sleeve |5. The carrier |2 is mounted on a. shaft I8 which is driven from the engine crankshaft by any suitable gearing. Through a ball-bearing assembly I6, the thrust of the weights II, developed by centrifugal force during rotation thereof, is transmitted to trunnions |1 carried by a. lever member I6. Said member is rigidly connected, as best shown in Figure 2, to a shaft |9. Said shaft is supported in side walls of the casing extending beyond one wall thereof. An arm is rigidly connected to the end of the shaft I9 and oscillates with the member I8.

An upwardly extending lever 2| on the member I8 is located between thrust flanges 22 of a control rack 23 of engine power controlling structure. Said rack is adapted to control the quantity of fuel injected by changing the angular position of the injection plunger. as shown, for example, in the above mentioned Baur Patent. The pump illustrated in part in this disclosure is completely shown, described, and claimed in the copending application Serial No. 330,750, led April 20, 1940, of E. A. Johnston et al., now Patent No. 2,287,478. Figures 10 and 11 are believed to adequately illustrate the pump in so far as its structure need be understood with respect to the present invention. Referring to these two figures, 10 and 11, said pump can be seen to have a casing 6| containing a vertically reciprocal plunger 62, which is urged downwardly by a spring 63' into engagement with a rim 64 journaled upon an eccentric 65 fixed for rotation with an enginedriven shaft 66. The spring 63 and said eccentric 65 cooperate to cause vertical reciprocating movement of the plunger 62 during rotation of the shaft 66.

During downward movement of the plunger 62, under the force of the spring 63, fuel is sucked downwardly into the upper end of a bore 61 for said plunger, through a filter element 68, and vertical passages 69 and 1|, AFigure l1, in 'ported blocks 12 and 13 of the casing, thence through channels 14 and 'I5 in the upper end of a member 16 containing the plunger bore, and through diametrically opposite ports 11 and 18 into said bore. Flow of fuel into the upper end of the bore 61 takes place upon the plunger being lowered sufficiently for the upper edge 19 of a sealing boss 8| thereon being disposed below such ports. During such downstroke of the plunger, a low pressure is incurred above the plunger for sucking the fuel into the space above the plunger because of the seating of a poppet valve member 82 upon its valve seat 83 in a fuel discharge passage 84. A spring 85 constantly urges the poppet valve member 82 seated. During the ensuing upstroke of the plunger, the sealing boss 8| covers the ports 11 and 18, causing the fuel to be compressed in that rpart of the bore above the plunger and to ultimately attain a pressure at which the poppet 82 is unseated, whereby the fuel under a high injection pressure is forced past said valve and thence through a channel 86 in an attaching bolt 81 for a conduit 88. From the bolt channel 88, the fuel passes into a. channel 88 in said conduit 88 for ultimate delivery to the engine combustion cylinders. The amount of fuel injected during each upward stroke of the plunger 62 is controlled by the rotational position of the plunger. It will be noted that the lower edge 9| of the portion of the sealing boss 8|, which is operable for sealing the port 11, is helical, wherefore the time in the upward movement of the plunger at which this lower helical edge 9| uncovers the port 81 can be varied by rotating the plunger to selected positions. High pressure is maintained in the bore above the plunger 62 so long as both of the ports 11 and 18 are sealed by the boss 8|. This boss is so constructed that the port 18 would always be covered during the compression stroke of the plunger. During the upward stroke of the plunger, upon the lower edge 8| of the boss 8| uncovering a portion of the port 11, the fluid pressure within the upper end of the bore will be immediately dissipated, since it will then be allowed to escape downwardly through a vertical gap 92 between the ends of the boss 8| and outwardly through the port 11. At this instance of the collapse of pressure within the cylinder, the poppet valve 82 will close and injection will cease. The amount of fuel injected is a function of the time during which the port 11 is sealed by the boss 8|. For example, when the plunger 62 is in the position illustrated in Figures 10 and l1, there will be a relatively large fuel injection, because that portion of the helical edge 9| for registering with the port 11 is spaced downwardly 9, relatively great distance from the upper edge 18 of the boss. Should, however, the plunger 82 be rotated clockwise, as viewed from above, for bringing a portion of the helical edge 9| spaced a less distance from the edge 18 into radial registry with the port 11, a less time would elapse between the closing of the port 11 by the upper edge 19 and the opening of such port by the upwardly moving lower edge 9|. The correspondingly shortened pressure portion of the plunger stroke causes a correspondingly diminished amount of injected fuel. The rotation of the plunger 62 is controlled by a sleeve 98 rotatable within the casing 6| and the rack 28. Gear teeth 9| on the sleeve 98 are meshed with teeth 95 on the rack so that axial movement of said rack will cause rotation of said sleeve. A lower internal peripheral fportion of the sleeve 93 is splined as indicated at 96, and these splines are meshed with radial projections 91 on a section of the plunger 62. This meshed relation of the splines 96 and the projections 91 permits vertical reciprocation of the pump plunger while providing means for adjusting the rotational position of the plunger.

Spaced vertically above the shaft |9, a second shaft 24 extends across the casing, being journaled in the walls thereof. Said shaft also extends from one casing wall at the same side as the extension of the shaft I9. A control member 25, shown in all the figures and in detail in Figures 3 and 4, is rigidly secured to the projecting end of a shaft 2l for oscillative advancive and retractive movement. A pair of members 26 are pivoted on 'pins 21 on the member 25. Said members have cammed upper faces 28 on which a spring 28 consisting of a plurality of laininations, or leaves, rests. The spring 29 is held in position by a cap screw 30 extending through a projecting portion 3| of the member 25 and through apertures at one end of the leaves of the spring. Said spring is a form of calibrated means for op- Jaccuser l posing force exerted by the centrifugally operated force exerting means Il.

The members 28 are provided with an adjustment in the form of set screws 22 threaded through the member 2l. `Said screws may be adjusted to vary the positions of the cam surfaces 22 with respect to the contacting bottom portion of thel spring 22. An adjustable stop for the spring 2l is also provided in the form of a cap screw 22 threaded through thel member 25 be.- tween the set screws 22. t.

Within the casing. a dependingA lever 24 is rigidly connected to the shaft 24. A link l22 pivotally connected to the lever' 24 is connected to-'one end of the tensionspring 26 which is another calibrated means for opposing force developed by the centrifugallyA operated force exerting means Ii. The springs 22 and 22 are biasing force devices since each exerts a force biasing the'engine power controlling structure 22 .in a power increasing direction when energized as shown in Fig. 9. The spring 26` is stronger and j constitutes the principal biasing force device since its force is used complementally with that developed by the weights il, whilejthe power. controlling structure 22 is in the normal load range for the engine. The spring 29 may be regarded as a power booster device since it is of its length by engagement with the cam surfaces 22 until the force necessary to deflect it will be suflicient to pick up the main spring 22 removing it from the stop 45. The leaf spring 29 is so designed as to have a controlled variable rate whereby the force necessary to deflect the spring a unit distance can be predetermined by formation of the cam surfaces 2l and adjustment of the stops 22 to bear the desired relation with respect to the force exerted by the centrifugal governor in the overload range of operation. As the spring is deflected the eil'ective support' for the spring on the cam members 22 is shortened thereby increasing the rate of the spring which is considered as the pressure necessary to deflect.

the spring a unit distance. The spring is so calibrated and supported that the force necessary to operable in opposition to and complementally with the force exerting means Il' for controlling the'amount of fuel delivered to the engine in the overload range. The other end of said spring is connected to a member 2l which is in turn pivotally connected to a speed adjusting arm 2l. Said'arm is mounted on a transverse -shaft 29.` An adjustable stop 4II limits the maximum speed position of the lever 22 while permitting Amovement in the other direction to reduce the speed of the engine. This stop 42 and the springs 2l and 22 which react therebetween and the inertial weights I i may be regarded as a force controlling means since they control'the effect of the force developed by these weights.

'rnc position of the arm 2| is such that en ariv instable engaging member 4| extending through the end of said arm engages the center of the leaf spring 29. An arched member`42, secured to the member 25, extends around the arm 2l and is provided with an adjustable stop 42 for limiting outward movement of the arm 2l. This acts as a maximum speed or fuel quantity inJec-f` tion for the governor device. A lug 44' projecting from the wall of the casing provides a mounting.

for curtailing or limiting means for the spring .26

in the form of a threaded stop 45 located to en,

gage the projecting portion 2l on't'he member 25. Said stop acts to relieve action of the main.

spring 26 on the governor, permitting, however;

the leaf spring 29 to act as long as it is deflected out of its initial unflexed position. A

The operation of the parts making up applicants improved governor device has been ex-l plained in connection with the description. To further point out the utility of the device and its improvement over the prior art, a more detailed explanation will be given.

Assuming that the engine is running at its full load position and at the maximum speed for such load, the governor weights will be swung outwardly to position shown in Figure 9. The

arm 20 will be engaged with the leaf spring 29,

said spring being completely flexed to engage the stop 22. At that point, the spring 22 will have increased in rate to have the amount of -force deflect the spring to its final loaded position against the stop 23 is suicient to lift the coil spring 26 off of the stop 45. This construction makes it possible to provide a smooth curve of fuel injection at different ranges of operation' and, moreover, provides means whereby the optimum fuel quantity can be injected during the maximum load condition and particularly during an overload condition of operation. So long 4as the engine operates at a speed close to the full load range for which the governor is designed.

the projecting portion 3I of the member 25 is outof contact with the stop 45.

When an additional load is encountered sufiicient to require power above that obtained by injection of the normal amount of fuel, the spring.

lines have been labeled with the vlegend Idle position," Normal load range, Full load, and Over load. If a further decrease in speed is brought about due to the load condition on the engine, the projecting portion 2| engages the stop 45 as shown in Figure 8, thereby removing the force of the spring 2l from the governor mechanism. The variable rate leaf spring 22 is then effective, as the speed further dies on, to move the control rack to the right in a calibrated movement dependingfupon the amount of speed decrease to inject'an additional amount of fuel per stroke. As previously stated, the spring 22 is formed and mounted so as to secure a variable ratel action; that is, an' action in which at diil'erent positions of the .spring dinerent amounts of force are required per unit of deflection-as comlpared with constant-rate springs such asy coil springs in which the amount of force per unit of deflection is uniform. During the overload operation following the setting of the projecting portion 2l on the stop 45, the fuel loaded spring 22- tends to straighten out at a continually lowering rate of force necessary per unit of movement, thereby injecting an additional amount of fuel per stroke. This amount takes up for the decrease in injection due tospeed and preferably gives an additional amount up to or slightly within the smoke range of the engine, presuming that the pump is being used on a compression ignition engine. 'In any event, an amount of fuel is injected in excess of the amount which could be used at full load.l high speed operation. When the load is removed from the engine, or is lightened suiiiciently that the engine speed increases,

necessary for deflection due to the shortening 15' the above steps are repeated in the reverse order.

l The arm 2l ilrst fiexes the variable rate spring 2l until a force is developed sufficient to pick up the main spring Il removing the projecting portion Il of the control member 2i from the stop 45.

It will be noted that adjustments have been YVshown at almost every point in the linkage making up applicants governor mechanism. Such adjustments may or may not be utilized depending upon the adjustment required in the particular engine and installation thereof. Also, it may not be necessary to utilize the stop u as the spring Il and the abutting members 28 may be constructed so that a resistance is built up during the initial movement of the arm 2l sujiicient to begin extension of the spring and to withstand the maximum force applied by the governor weights against said spring.

It is to be understood that applicants have shown and described only a preferred embodiment of their improved governor mechanism for fuel injection pumps, and that they claim all modifications falling within the scope of the appended claims.

what is claimed is:

l. In a governor mechanism for fuel injection pumps, and in combination a member adapted to regulate the quantity of injected fuel, centrifugal means. lever mechanism connecting said centrifugal means to said reciprocable member, a control member pivoted for oscillation, a main governor spring connected to said member and operated to urge it in one angular direction, a stop positioned to limit the movement of said member under the action of said spring, a variable rate spring requiring an increasing amount of :force for each successive unit of deflection carried by said control member, means carried by said lever mechanism engageable with said variable rate spring and effective to deilect said spring under a certain range of movement of the lever mechanism as brought about by said governor weights, said lever mechanism being effective thereafter to oscillate the control member against the main governor spring.

2. In a governor mechanism for fuel injection pumps for engines, and in combination a fuel regulating member, centrifugal means adapted to be driven by the engine. lever mechanism connected to said centrifugal means and to the fuel regulating member, the force developed by said centrifugal means being in a direction to decrease the amount of fuel injected, a control member, a torque control spring mounted between said control member and said lever mechanism in a position to be deflected under a certain range of movement of the lever mechanism as brought. about by said centrifugal means, a main governor spring connected to the control member and operative to urge said member in a direction to increase the amount of fuel injected, a stop positioned to limit the movement of said member in said direction under the action of said spring upon a decrease in engine speed, said torque control spring being thereafter solely effective to control the injection of increased amounts of fuel depending upon the force necessary to overcome the centrifugal means.

3. In a governor mechanism for fuel injection pumps, and in combination a member adapted to regulate the quantity of injected fuel, centrifugal means, lever mechanism connecting said centrifpivoted for oscillation, a main governor spring connected to said member and operative to urge it ugal means to said member, a control member .Y

in one angular direction. a stop positioned to limit the movement of said member under the action of said spring, a variable rate spring requiring an increasing amount of lforce for each successive unit of deilection carried by said control member, means carried by said lever mechanism engageable with said variable rate spring and effective to denect the rsaid spring under a certain range of movement of the lever mechanism as brought about by said governor weights. stop means carried by the control member for limiting the deflection of the auxiliary spring, said lever mechanism being effective after engagement with the stop means to oscillate the control member against the force exerted by the main governor spring.

4. In a governor mechanism for fuel injection pumps, and in combination -a reciprocable member adapted to regulate the quantity of injected fuel, a rotating shaft, a sleeve mounted for reciprocation on said shaft, centrifugal weights pivoted for rotation with said shaft and operable to reciprocate said sleeve, pivoted lever mechanism connecting said sleeve to said reciprocable member, a control member pivoted for oscillation, a main governor spring connected to said member and operative to urge it in one angular direction, a stop positioned to limit the movement of said member under the action of said spring, a variable rate spring requiring an increasing amount of force for each successive unit of deflection carried by said control member, an arm carried for oscillation with said lever mechanism engageable with said variable rate spring. said arm being effective to deflect the variable rate spring under a certain range of movement of the lever mechanism as brought about by said governor weights, said arm being effective thereafter to oscillate the control member against the main governor spring.

5. In a governor mechanism for fuel injection pumps. and in combination a reciprocable member adapted to regulate the quantity of injected fuel, a rotating shaft, a sleeve mounted for reciprocation on said shaft, centrifugal weights pivoted for rotation with said shaft and operable to reciprocate said sleeve, pivoted lever mechanism connecting said sleeve to said reciprocable member, a control member pivoted for oscillation, speed control means including an adjustable member, a main governor spring connected at one of its ends to said control member and operative to urge it in one angular direction, said spring being connected at its other end to said adjustable member, a stop positioned to limit the movement of said control member under the action of said spring, a variable rate spring requiring an increasing amount of force for each successive unit of deflection carried by said control member, an arm carried for oscillation with said lever mechanism engageable with said variable rate spring, said arm being effective to deilect the variable rate spring under a certain range of movement of the lever mechanism as brought about by said governor weights, said arm being effective thereafter to oscillate the control member against the main governor spring.

6. In a governor mechanism for fuel injection pumps, and in combination a reciprocable member adapted to regulate the quantity of injected fuel, a rotating shaft, a sleeve mounted for reciprocation on said shaft, centrifugal weights pivoted for rotation with said shaft and operable to reciprocate said sleeve, pivoted lever mechanism connecting said sleeve to said reciprocable .a inmber, i. control member pivoted for oscillation, a main governor spring connected to said member and operative to urge it in one angular direction. a stop positioned to limit the movement of said member under th'e action of said spring, a variable rate spring requiring an increasing amount of force for each successive unit of deflection carried by said control member, an arm carried for oscillation with said lever mechanism engageable with said variable rate spring, stop means positioned to limit the yielding of said variable rate spring, said arm being effective to deect the variable rate spring under a certain range of movement of the lever mechanism as brought about by said governor weights, said arm being efl'ective thereafter to oscillate the control member against the main governor spring.

' 7. In a governor mechanism for fuel injection pumps, and in combination a reciprocable member adapted to regulate the quantity of injected fuel, a rotating shaft, a sleeve mounted for reciprocation on said shaft, centrifugal weights pivoted forrotation with said shaft and operable to reciprocate said sleeve, pivoted lever mechanism connecting said sleeve to said reciprocable member, a control member pivoted for oscillation, a main governor spring connected to said member and operative to urge it in one angular direction, a stop positioned to limit the movement of said member under the action of said' spring, a variable rate leaf spring requiring an increasing I amount of force for each successive unit of deiiection kcarried by said control member, an arm carried for oscillation with said lever mechanism engageable with an intermediate portion of said spring. said arm being effective to deflect thev leaf spring under a certain range of movement of the lever mechanism as brought about by said governor weights, said arm being effective thereafter to oscillate the control member against the main governor spring.

8. In a governor mechanism for fuel injection pumps having a casing, and in combination a reciprocable member in the casing operable to regulate the quantity of injected fuel, centrifugal means in the casing adapted to be driven by the engine, lever mechanism pivoted on the casing connecting said centrifugal means to said reciprocable member, a control member pivoted on the casing, a main governor spring connected to said control member at one end and yto the casing at its other end and operative to urge said member in one angular direction, a stop on the casing positioned to limit the movement of said member under the action of said spring, an auxiliary variable rate leaf spring requiring an increasing amount of force for each successive unit of deiiection carried by said control member, an arm carried by said lever mechanism engageable with said auxiliary spring and effective to deilect said spring under a certain range of movement of the lever m as brought about by the centrifugal means, said lever mechanism being elective in another range to move the control member against the force exerted thereon by the main governor spring.

9. An engine governor comprisingl a force-exerting means capable of exerting a force variable in accordance with the speed of an engine to be governed. an engine power controlling structure force, a nrst calibrated means for opposing the force of said force-exerting means so the resultant of their forces is effective to determine said adjustment of the structure, c urtailing means operable to preclude such opposition of said calibrated means while the force of said force-exerting means is less than a predetermined minimum, and a second and diilerently calibrated means of variable opposing rate for opposing the force of said force-exerting means so the resultant of their forces is effective to determine said adjustment of the structure while the force of said force-exerting means is less than said predetermined minimum.

adjustment of said structure, said force control- 1 ling means comprising force-reaction means and distortable principal and power-booster biasing devices disposed in series between said force reaction means and said force-exerting means to ,oppose the force exerted by the latter, said devices being energized when distorted pursuant to opposing the force of said force-exerting means and the power-booster device opposing distortion at variable rate increasing in accordance with the magnitude of its distortion, the booster device being substantially completely energizabie by and pursuant to a subnormal force of the force-exerting means, and the principal biasing device being energizable by and pursuant to only normal forces of the force-exerting means and hence subsequent to such energization of the booster biasing device.

ll. An engine governor comprising a forceexerting means capable of exerting a force variable in normal and subnormal ranges in accordance with speeds in normal and subnormal ranges of an engine to be governed,4 an engine power controlling structure subjected to the forceA of e said force-exerting means and adjustable under subjected to the force of said force-exerting A.

means and adjustable under the influence therei' of into positions determinative of engine power the influence thereof into positions determinative of engine power as an inverse function of the magnitude of said force, and force-controlling means associated with said force-exerting means for controlling the force exerted thereby in the adjustment of said structure. said force-controlling means comprising a member capable of advancive and retractive movement, limiting means providing a retractive limit for said member, a

distortable principal biasing device connected with said member for retractively urging the same toward said limiting means, and a distortable booster biasing device disposed between said member and said force-exerting means for imparting force from said force-exerting means through said member to said principal biasing device, each of said devices being energized to exert an opposing or biasing force when distorted by the application of force thereto by the forceexerting means and the power-booster device opposing distortion at a variable rate increasing in accordance with the magnitude of its distortion, the .booster biasing device being calibrated for enas an inverse function of the magnitude of said 7s ergization by subnormal forces imposed thereon from the force-exerting means and the principal biasing device being calibrated for energization by forces of the normal range and of a magnitude at least in the upper position oi' the subnormal range wherefore said member is advanced from its retraction limit subsequent to at least partial energization of the booster biasing device.

12. An engine governor comprising a forceexerting means capable of exerting a force variable in normal and subnormal ranges in accordance with speeds in normal and subnormal ranges of an engine to be governed. an engine power controlling structure subjected to the force oi said force-exerting means' and adjustable under the influence thereof into positions determinatlve ot engine power as an inverse function of the manitude of said force, and force-controlling means including biasing force devices separately operable for exerting biasing force of diilerent characteristics in opposition to and for controlling the force of the force-exerting means in adjusting said structure, one of said devices being a normal force range device operable in opposition to and complementally with the force-exerting means only when the latter is exerting force of a. magnitude at least equal to those in the upper portion of the subnormal range, a second of said devices being a power-booster device eiectively operable in opposition to and complementally with the force-exerting means only while the latter is exerting force of a magnitude not exceeding those in the subnormal range and said second device being operable during such comlplemental opposition to the force-exerting means to oppose the force-'thereof at a variable rate decreasing in accordance with decrease in magnitude of the subnormal torce ot the force-exerting means.

POSTER BUCK.

FRED W. BARBKNECHT.

RAYMON BOWERS.

REFERENCES CITED The following references are of record in the ille oi' this patent:

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